Project Summary/Abstract This application is a renewal of U24 AA022003 (PI, Kahler), a resource core that has been coding mechanisms of behavior change in alcohol-HIV interventions conducted by the Brown University Alcohol Research Center on HIV (ARCH) and Yale University. In this renewal, the core has been expanded to incorporate a broader range of functions and to support work being done in the Southern HIV & Alcohol Research Consortium (SHARC) and work conducted in collaboration between the Brown ARCH and SHARC. Specifically, this Behavioral Science and Biostatistics Resource Core (BSBRC) will support state-of-the-art methods for understanding the role that alcohol has on health outcomes in people living with HIV (PLWH) and for implementing and understanding effective interventions to reduce drinking, enhance engagement in HIV care, and reduce sexual risk behaviors in PLWH. Towards these ends, the BSBRC will bring together expertise in (a) the effective implementation of contingency management (CM) and motivational interventions (MI) to reduce drinking and improve related HIV outcomes, (b) the study of mechanisms of behavior change in alcohol counseling and HIV care, and (c) the use of sophisticated data analytic methods for observational and experimental data. This multidisciplinary team of experts will share intellectual resources and conduct work across geographically and racially/ethnically diverse populations to forward science on how best to address excessive alcohol use, a key contributor to HIV transmission, morbidity, and mortality in PLWH. Specific objectives of the core include: (1) to provide expertise in Contingency Management procedures and in the use of the SCRAM Continuous Alcohol Monitor biosensor, (2) to train and supervise staff on the implementation of an evidence-based MI to reduce alcohol use using high definition videoconferencing; (3) to conduct state-of- the-art, clinically relevant research on mechanisms of behavior change in alcohol interventions among PLWH including examination of the effects that videoconferencing and CM have on the therapeutic processes hypothesized in MI change theory; (4) to provide data management and biostatistical leadership and support to the SHARC U01 and, when resources permit, to other CHAART consortia. The core will contribute to the overall success of the SHARC and ARCH projects it supports while also forwarding science in intervention and statistical methodology with a particular focus on the intersection between alcohol and HIV. Thus, this resource core can make a substantial impact in reducing the burden of disease associated with excessive drinking and HIV.